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Spontaneous development of dermatitis in DS-Nh mice under specific pathogen-free conditions
Akira Watanabe1, Mitsuo Takeuchi, Masafumi Nagata
1Developmental Research Laboratories, Shionogi & Co., Ltd., Futaba-cho, Toyonaka, Osaka 561-0825, Japan.
Abstract:
Spontaneous development of dermatitis in DS-Nh mice under specific pathogen-free conditions was examined to verify the hypothesis [Exp. Anim. 46: 225-229, 1997] that Stapylococcus aureus (S. aureus) infection is causally associated with the dermatitis. Observation of the mice up to 28 weeks of age indicated that obvious dermatitis does occur under S. aureus-free conditions, though the incidence was low (six of 42 females and two of 90 males). Skin lesions in the absence of this bacterium showed histological changes very similar to those that can be observed under conventional conditions. In addition, hyperproduction of serum IgE was demonstrated in the dermatitis-positive mouse. These findings suggested that the dermatitis is triggered by IgE-mediated allergic reactions.
Insights
Dermatitis in mice can occur without Staphylococcus aureus infection, suggesting IgE-mediated allergic reactions may be the cause. Further research into allergic triggers for mouse dermatitis is warranted.
Area of Science:
- Immunology
- Dermatology
- Animal Models
Background:
- Spontaneous dermatitis is observed in DS-Nh mice.
- A previous hypothesis linked Staphylococcus aureus infection to this dermatitis.
Purpose of the Study:
- To investigate the causal relationship between Staphylococcus aureus infection and spontaneous dermatitis in DS-Nh mice.
- To explore alternative causes of dermatitis in these mice.
Main Methods:
- DS-Nh mice were observed up to 28 weeks of age under specific pathogen-free conditions.
- Histological examination of skin lesions was performed.
- Serum IgE levels were measured in dermatitis-positive mice.
Main Results:
- Dermatitis developed in S. aureus-free mice, albeit at a low incidence (6/42 females, 2/90 males).
- Histological findings in S. aureus-free mice were similar to those with conventional exposure.
- Dermatitis-positive mice exhibited hyperproduction of serum IgE.
Conclusions:
- Staphylococcus aureus infection is not the sole cause of spontaneous dermatitis in DS-Nh mice.
- The development of dermatitis in these mice is likely triggered by IgE-mediated allergic reactions.
- Further investigation into allergic mechanisms underlying mouse dermatitis is recommended.